Compound interest calculator
Balance after 30 years
$660,849
Future dollars, before taxes
- Total deposited
- $190,000
- Investment growth
- $470,849
- Value in today’s dollars
- $315,055
| Year | Savings | Total deposited |
|---|---|---|
| 0 | $10,000 | $10,000 |
| 1 | $16,890 | $16,000 |
| 2 | $24,263 | $22,000 |
| 3 | $32,151 | $28,000 |
| 4 | $40,592 | $34,000 |
| 5 | $49,623 | $40,000 |
| 6 | $59,287 | $46,000 |
| 7 | $69,627 | $52,000 |
| 8 | $80,692 | $58,000 |
| 9 | $92,530 | $64,000 |
| 10 | $105,197 | $70,000 |
| 11 | $118,751 | $76,000 |
| 12 | $133,254 | $82,000 |
| 13 | $148,772 | $88,000 |
| 14 | $165,376 | $94,000 |
| 15 | $183,143 | $100,000 |
| 16 | $202,153 | $106,000 |
| 17 | $222,494 | $112,000 |
| 18 | $244,258 | $118,000 |
| 19 | $267,547 | $124,000 |
| 20 | $292,465 | $130,000 |
| 21 | $319,128 | $136,000 |
| 22 | $347,657 | $142,000 |
| 23 | $378,183 | $148,000 |
| 24 | $410,846 | $154,000 |
| 25 | $445,795 | $160,000 |
| 26 | $483,191 | $166,000 |
| 27 | $523,205 | $172,000 |
| 28 | $566,019 | $178,000 |
| 29 | $611,831 | $184,000 |
| 30 | $660,849 | $190,000 |
Deposits stay the same dollar amount and arrive at the end of each month. The annual return is an effective annual rate (APY), converted to its equivalent monthly rate.
How this is calculatedHow this calculator works
Investor.gov’s compound interest calculatorFuture value = starting balance × (1 + r)^n + monthly deposit × ((1 + r)^n − 1) / r
The starting balance grows for the full period. Each monthly contribution arrives at the end of the month, so the final deposit earns no interest within the selected horizon.
In the formula, r is the monthly rate and n is the number of months. At 0% return, future value is simply starting balance plus all deposits. The annual rate is effective (APY), not APR. We convert it with (1 + annual rate)^(1/12) − 1, so a 7% rate grows an untouched balance by exactly 7% over a year.
Contributions remain fixed in nominal dollars. The chart shows future dollars. The purchasing-power result discounts the ending balance by your inflation assumption. Tax is not deducted; enter a return after investment fees.